#include "bits/stdc++.h"
using namespace std;

#define f first
#define s second
#define pi pair<int,int>
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define For(i,a) FOR(i,0,a)
#define trav(a,b) for(auto& a:b)
#define all(x) begin(x),end(x)
#define sz(x) (int)(x.size())
#define vi vector<int>
#define vpi vector<pi>
#define pb push_back
#define ins insert
#define f first
#define f first

const int MX=305;
const int MX2=MX*MX;

vpi adj[MX][2];
bool on[MX2];
bool done[MX][2],vis[MX][2];
vpi edg;

bool dfs(int n, int typ){
    // cout<<"HI: "<<n<<" "<<typ<<endl;
    if(vis[n][typ])return false;
    vis[n][typ]=true;

    if(typ && !done[n][typ]){
        // cout<<"GOOD "<<n<<" "<<typ<<endl;
        return true;
    }
    trav(x,adj[n][typ]){
        if(typ==0){
            if(!on[x.s]){
                bool z=dfs(x.f,1);
                if(z){
                    done[n][0]=true;
                    done[x.f][1]=true;
                    on[x.s]=true;
                    return true;
                }
            }
        } else {
            if(on[x.s]){
                bool z=dfs(x.f,0);
                if(z){
                    on[x.s]=false;
                    return true;
                }
            }
        }
    }
    return false;
}

int main(){
    int L,R,M;cin>>L>>R>>M;
    For(i,M){
        int a,b;cin>>a>>b;
        adj[a][0].pb({b,i});
        adj[b][1].pb({a,i});
        edg.pb({a,b});
    }
    For(i,L){
        if(!done[i][0]){
            memset(vis,false,sizeof vis);
            dfs(i,0);
        }
        // cout<<"DONE: "<<i<<endl;
    }
    int cnt=0;
    For(i,L)if(done[i][0])cnt++;
    cout<<cnt<<endl;
    For(i,M)if(on[i]){
        pi tmp=edg[i];
        cout<<tmp.f<<" "<<tmp.s<<endl;
    }
}